It's between Buchnevich and Thomas right now, as others have mentioned. I think it depends on which type of player you value more.
Player A: Center. Elite passing, vision, skating, and stickhandling. Pure playmaker that can consistently get the puck to players in dangerous shooting positions. Has a good shot but seldom uses it. Shies away from most physicality, but elusive with the puck. Great offensively, ok defensively. Strong on the dot.
Player B: Winger. Strong to elite at nearly all facets of the game. No real weaknesses. Versatile, can play just about any style you want him to or in any situation. Great offensively, great defensively. Dangerous with the puck, and smart/tenacious without the puck. Seems to have good chemistry with just about anyone you put him with.